Evaporation mask, method of fabricating organic electroluminescent device using the same, and organic electroluminescent device

ABSTRACT

An evaporation mask, a method of manufacturing an organic electroluminescent device using the evaporation mask, and an organic electroluminescent device manufactured by the method are provided. The evaporation mask is formed of a thin film and is drawn taut by application of tension. The evaporation mask includes at least one mask unit, the mask unit including a plurality of main apertures, and a plurality of first dummy apertures formed adjacent to outermost ones of the main apertures in a direction in which tension is applied to the evaporation mask.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Japanese Application No.2002-347977, filed Nov. 29, 2002, in the Japanese Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an evaporation mask, and, moreparticularly, to an evaporation mask in which the pitch between adjacentapertures can be kept even when a tension is applied, a method offabricating an organic electroluminescent (EL) device using theevaporation mask, and an organic EL device manufactured using the abovemethod.

[0004] 2. Description of the Related Art

[0005] EL devices, which are spontaneous light-emitting display devices,provide a wide viewing angle, good contrast, and a high response speed.Accordingly, much attention is being focused on EL devices because theycan be used as a next-generation display device.

[0006] EL devices are classified as inorganic EL devices or organic ELdevices, depending on what material is used to form a light-emittinglayer. Organic EL devices have a higher brightness and fasterresponsivity than inorganic EL devices, and can provide color display,so they are presently being more actively developed.

[0007] Organic EL devices include first electrodes formed in apredetermined pattern on a transparent insulating substrate, an organicfilm formed on the first electrodes by vacuum evaporation, and secondelectrodes formed on the organic film such that the first and secondelectrodes cross each other.

[0008] In the manufacture of the organic EL devices having such astructure, the first electrodes are typically formed by patterningindium tin oxide (ITO) using a photolithographic method.

[0009] Such a photolithographic method can be used before an organicfilm is formed, but causes a problem when it is used after an organicfilm is formed. Because the organic film is very sensitive to water, itmust be thoroughly isolated from water both while being fabricated andafter the fabrication. Consequently, a photolithographic methodincluding an exposure to water during pealing-off and etching of aresist is not suitable for patterning the organic film and the secondelectrode layer.

[0010] This problem is usually solved by vacuum-depositing an organiclight emissive material for the organic film and a material for thesecond electrode layer using a patterned mask. In particular, the secondelectrode layer can be patterned using a cathode separator, but it isknown that a vacuum evaporation method using an evaporation mask is themost appropriate way to pattern a low molecular organic film.

[0011] A technique of patterning an organic film or a second electrodelayer using a mask is very important in the manufacture of full-colororganic EL devices.

[0012] Examples of conventional full-color organic EL device coloringmethods include a three-color independent evaporation method, in whichred (R), green (G), and blue (B) color pixels are independentlydeposited on a substrate, a color conversion method (CCM), in which acolor conversion layer is formed on a light emissive surface using ablue light source, and a color filtering method, which uses a whitelight source and a color filter. The three-color independent evaporationmethod has attracted much attention because it is simple to perform, andprovides a high color purity and efficiency.

[0013] In the three-color independent evaporation method, the R, G, andB color pixels are independently deposited on a substrate using anevaporation mask. Here, the evaporation mask must be made of a materialwith a low thermal expansion coefficient in order to prevent thermaldeformation, and also must be magnetic if the evaporation mask is to beadhered to the substrate using a magnet. More importantly, theevaporation mask must be highly accurate. In particular, the positionsof deposited pixels, that is, the widths of pattern apertures, must behighly accurate, and a high accuracy of a total mask pitch is alsorequired. For example, if an organic EL device must have a high finenessof 130 ppi or greater and an aperture efficiency of 50% or greater,deviation in the widths of apertures of the evaporation mask must notexceed ±5 μm, and deviation in the total mask pitch must not exceed ±10μm.

[0014] As shown in FIG. 1, an evaporation mask 10 used to deposit anorganic film or electrodes when fabricating an organic EL device istypically supported by a frame 20, so that the evaporation mask 10 isdrawn taut. In the mask 10, a plurality of mask units 12, allowing asingle organic EL device to be formed thereon, are formed on a singlemetal thin plate 11.

[0015] Because the evaporation mask 10 is thinly formed and minutelypatterned, if it is used without any treatment, some parts of it maydroop, preventing accurate patterning. Accordingly, as shown in FIG. 1,optimal tension in the x- and y-axis directions is applied to theevaporation mask 10 to obtain a predetermined accuracy of a total pitch(Pt), and the taut evaporation mask 10 is coupled to the mask frame 20.Upon coupling, it is important to not change the Pt accuracy. Thecoupling of the evaporation mask 10 to the mask frame 20 can be achievedby various methods such as using an adhesive, laser welding, orresistance welding.

[0016] Each of the mask units 12 includes a pattern of apertures. Asshown in FIG. 1, each of the mask units 12 may have strip-like apertureselongated in the y-axis direction. However, the tension makes itdifficult for the outermost apertures of each of the mask units 12 tomaintain a predetermined level of accuracy.

[0017]FIG. 2 is a cross-section of a mask unit 12 taken along line I-Iof FIG. 1, which shows apertures 13 formed in the mask unit 12. As shownin FIG. 2, a shielding portion 14 is provided between adjacent apertures13, and outermost apertures 13 a are each defined by a shield portion 14and a rib 15 between adjacent mask units.

[0018] As shown in FIG. 2, if tension is applied to the evaporation mask10 having the apertures 13 in the x- and y-axis directions as shown inFIG. 1, an edge portion 15 a of the rib 15 may curve upward. Suchdeformation of the edge portion 15 a of the rib 15 degrades the accuracyof the widths of each of the outermost apertures 13 a. Hence, theaccuracy of deposition performed on an organic emissive film through theoutermost apertures 13 a is degraded, and, consequently, accuratepatterning of the organic emissive film is not accomplished outside apanel. If an edge of a rib between adjacent mask units is deformed, thedeformed rib contacts the organic emissive film, thus generating adefect such as a dark point or a pixel short-circuit on the perimeter ofa panel.

[0019] As shown in FIG. 3, this problem affects the outermost mask unitsmore than other mask units, thus degrading the accuracy of the totalmask pitch.

[0020] In other words, as shown in FIG. 3, particularly, mask units 12 aand 12 b located at the outermost sides in the direction perpendicularto the direction of the length of apertures 13, that is, in the x-axisdirection where tension is applied, may be deformed more seriously thanother mask units 12 due to the tension applied in the x-axis direction.Accordingly, the accuracy of a total pitch (Pt), the gap between a line16 a connecting the edges of the outer ribs of the mask units 12 a and aline 16 b connecting the edges of the outer ribs of the mask units 12 b,decreases, resulting in degradation of the accuracy of patterning of themask units 12.

[0021] A mask that overcomes the problem of the deformation of stripsthat form slits due to thermal expansion of the mask is disclosed inJapanese Patent Publication No. 2001-247961. The disclosed mask includesa mask portion and a screen portion. The mask portion is an evaporationmask used to form a patterning film on a substrate by evaporation, andhas partitions for defining a plurality of first apertures. The screenportion contains a magnetic material and has a plurality of secondapertures smaller than the first apertures. The second apertures aredisposed on the first apertures of the mask portion.

[0022] Japanese Patent Publication No. 2001-273979 discloses thestructure of a magnetic mask. Japanese Patent Publication No.2001-254169 discloses an evaporation mask frame assembly in which apatterned mask masks a deposition area while adhering closely to amaterial to be deposited, and has fine gaps and fine patterns. The finepatterns of the patterned mask are supported by fine ribs.

[0023] These disclosed masks adhere closely to a material to bedeposited because they are formed of a magnetic material. However, thesemasks still have a problem of losing accuracy due to the deformation ofthe outermost apertures during a tensing operation.

[0024] Japanese Patent Publication No. 2002-9098 discloses a patternforming apparatus for preventing a pre-formed film on a substrate frombeing damaged due to a mask coming partially off of a frame due to athermal expansion during evaporation. The pattern forming apparatusincludes a support which is formed to be larger than the mask, and has adent portion onto which the mask is seated. The support prevents a maskfrom becoming rippled due to thermal expansion during the formation of afilm. Also, by forming a magnetic element on the side of the mask facingaway from the support, the magnetic element makes the mask closer to thesubstrate so that a space between the mask and the support is created.This space contributes to cooling the mask.

[0025] However, because the disclosed mask having slits is not firmlysupported by the frame, the location of the mask cannot be accuratelycontrolled. In particular, in the case of organic EL devices that musthave very thin evaporation masks to accomplish highly accuratepatterning, the location of the evaporation mask may be changed duringevaporation.

[0026] Japanese Patent Publication No. 2002-8859 discloses a patternforming apparatus for preventing a mask from being expanded by heatduring the formation of a film, in which a liquid path is formed withina frame which supports the mask, and a cooling solution circulateswithin the liquid path. However, this invention also overlooks thepossibility of tensions and apertures becoming inaccurate duringfixation of the mask into the frame.

[0027] Japanese Patent Publication Nos. 2000-48954, 2000-173769,2001-203079, and 2001-110567 disclose metal masks includingsupplementary lines to prevent drooping of a mask shield between themask and a frame. Like the above-disclosed masks, these masks may bestretched and warped while being fixed onto a frame after applyingtension in order to accomplish highly accurate patterning.

SUMMARY OF THE INVENTION

[0028] The present invention provides an evaporation mask that reducesdeviation of patterns by reducing variation in the accuracy of thewidths of apertures that may be caused by supporting a taut evaporationmask, a method of manufacturing an organic EL device using theevaporation mask, and an organic EL device manufactured by the method.

[0029] The present invention also provides an evaporation mask thatimproves pattern accuracy by compensating for a total pitch when tensionis applied to the evaporation mask, a method of manufacturing an organicEL device using the evaporation mask, and an organic EL devicemanufactured by the method.

[0030] Additional aspects and/or advantages of the invention will be setforth in part in the description which follows and, in part, will beobvious from the description, or may be learned by practice of theinvention.

[0031] According to an aspect of the present invention, there isprovided an evaporation mask formed of a thin film, wherein theevaporation mask is drawn taut by application of tension and comprisesat least one mask unit. The mask unit includes a plurality of mainapertures and a plurality of first dummy apertures formed adjacent tooutermost ones of the main apertures in a direction in which tension isapplied to the evaporation mask.

[0032] The main apertures may form an effective deposition area, and thefirst dummy apertures may form an ineffective deposition area.

[0033] At least one of the first dummy apertures may be formed parallelto the main apertures, and at least another one of the first dummyapertures may be formed perpendicular to the main apertures.

[0034] The evaporation mask may comprise at least two mask units, andmay further comprise a plurality of second dummy apertures formedoutside and adjacent to the outermost mask units in the direction inwhich tension is applied to the evaporation mask.

[0035] The second dummy apertures may be formed outside the effectivedeposition areas where the mask units are formed.

[0036] Alternatively, at least one of the second dummy apertures may beformed parallel to the main apertures of the mask units, and at leastanother one of the second dummy apertures may be formed perpendicular tothe main apertures.

[0037] According to an aspect of the present invention, there isprovided another evaporation mask formed of a thin film, wherein theevaporation mask is drawn taut by application of tension. Theevaporation mask includes at least two mask units each having at leastone main aperture and at least one second dummy aperture formed outsideand adjacent to the mask units located at the outermost sides in thedirection in which tension is applied to the evaporation mask.

[0038] The at least one main aperture of each of the mask units may beused to form an effective deposition area, and the at least one seconddummy aperture may be formed outside of the effective deposition areaswhere the mask units are formed.

[0039] Alternatively, the at least one second dummy aperture maycomprise at least two second dummy apertures, wherein at least one ofthe second dummy apertures may be formed parallel to the at least onemain aperture of the mask units, and at least another one of the seconddummy apertures may be formed perpendicular to the at least one mainaperture.

[0040] According to another aspect of the present invention, there isprovided a method of manufacturing an organic electroluminescent (EL)device. In this method, first electrodes are formed on a substrate.Next, an evaporation mask to form an organic film is disposed over thesubstrate. Here, the evaporation mask is drawn taut by application oftension and has at least one mask unit. The mask unit comprises aplurality of main apertures and a plurality of first dummy aperturesformed adjacent to outmost main apertures in a direction in whichtension is applied to the evaporation mask. The organic film comprisesan effective luminescent area formed to cover at least the firstelectrodes by evaporating an organic material containing an organicluminescent material through the main apertures. At this time, a firstdummy pattern area is formed outside the effective luminescent areathrough the first dummy apertures. Thereafter, second electrodes areformed on the organic film so that the effective luminescent area isformed at an area where the first and second electrodes overlap.Finally, the resulting structure is sealed.

[0041] At least one of the first dummy apertures may be formed parallelto the main apertures, and at least another one of the first dummyapertures may be formed perpendicular to the main apertures.

[0042] At least two organic EL devices may be manufactured in a singleprocess, and the evaporation mask may comprise at least two mask units,through each of which the organic film of a single organic EL device canbe deposited, and a plurality of second dummy apertures outside andadjacent to outermost ones of the mask units in the direction in whichtension is applied to the evaporation mask.

[0043] The second dummy apertures of the evaporation mask may be locatedoutside the effective luminescent areas of the organic EL devices thatmay be deposited by the outermost mask units adjacent to the seconddummy apertures.

[0044] At least one of the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least one of the seconddummy apertures may be formed perpendicular to the main apertures.

[0045] To form the second electrodes, first, an evaporation mask to formthe second electrodes may be disposed over the substrate. Here, theevaporation mask is drawn taut by application of tension and has atleast one mask unit. The mask unit comprises a plurality of mainapertures and a plurality of first dummy apertures formed adjacent tothe outermost main apertures in the direction in which tension isapplied to the evaporation mask. Then, the second electrodes may beformed on the effective luminescent area through the main apertures, anda second dummy pattern area may be formed outside the effectiveluminescent area through the first dummy apertures.

[0046] At least one of the first dummy apertures may be formed parallelto the main apertures, and at least another one of the first dummyapertures may be formed perpendicular to the main apertures.

[0047] At least two organic EL devices may be manufactured in a singleprocess. The evaporation mask may comprise at least two mask units,through each of which the second electrodes of a single organic ELdevice can be deposited, and a plurality of second dummy aperturesoutside and adjacent to the outermost mask units in the direction inwhich tension is applied to the evaporation mask.

[0048] The second dummy apertures may be located outside the effectiveluminescent areas of the organic EL devices that are deposited by theoutermost mask units adjacent to the second dummy apertures.

[0049] At least one of the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least another one of thesecond dummy apertures may be formed perpendicular to the mainapertures.

[0050] At least two organic EL devices may be manufactured in a singleprocess. The second electrodes may be formed using an evaporation maskdrawn taut by application of tension and having at least two mask units,through which the second electrodes of the organic EL device can bedeposited. The evaporation mask may comprise a plurality of second dummyaperture outside and adjacent to outermost mask units in the directionin which tension is applied to the evaporation mask.

[0051] The second dummy apertures may be located outside the effectiveluminescent areas of the organic EL devices that are deposited by theoutermost mask units adjacent to the second dummy apertures.

[0052] At least one of the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least another one of thesecond dummy apertures may be formed perpendicular to the mainapertures.

[0053] According to another aspect of the present invention, there isprovided another method of manufacturing an organic EL device. In thismethod, first electrodes for an organic EL device are formed on asubstrate. Next, an evaporation mask to form an organic film is disposedover the substrate. Here, the evaporation mask is drawn taut byapplication of tension and includes at least two mask units. Each of themask units comprises a plurality of main apertures and a plurality ofsecond dummy apertures formed outside and adjacent to outermost ones ofthe mask units in a direction in which tension is applied to theevaporation mask. The organic film comprising an effective luminescentarea is formed to cover at least the first electrodes by evaporating anorganic material containing an organic luminescent material through themain apertures of each of the mask units. Thereafter, second electrodesare formed on the organic film so that the effective luminescent area isformed at an area where the first and second electrodes overlap.Finally, the resulting structure is sealed.

[0054] The second dummy apertures may be located outside the effectiveluminescent areas of the organic EL devices that are deposited byoutermost ones of the mask units adjacent to the second dummy apertures.

[0055] Alternatively, the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least another one of thesecond dummy apertures may be formed perpendicular to the mainapertures.

[0056] In an alternative process of forming the second electrodes, anevaporation mask to form the second electrodes may be disposed over thesubstrate. Here, the evaporation mask may be drawn taut by applicationof tension and includes at least two mask units. Each of the mask unitsmay comprise a plurality of main apertures and a plurality of firstdummy apertures formed adjacent to the outermost main apertures in thedirection in which tension is applied to the evaporation mask. Then, thesecond electrodes may be formed on each of the effective luminescentareas through the main apertures, and a second dummy pattern area may beformed outside each of the effective luminescent areas through the firstdummy apertures.

[0057] At least one of the first dummy apertures may be formed parallelto the main apertures, and at least another one of the first dummyapertures may be formed perpendicular to the main apertures.

[0058] The evaporation mask may comprise a plurality of second dummyapertures outside and adjacent to the outermost mask units in thedirection in which tension is applied to the evaporation mask.

[0059] The second dummy apertures of the evaporation mask may be locatedoutside the effective luminescent areas of the organic EL devices thatare deposited by the outermost mask units adjacent to the second dummyapertures.

[0060] At least one of the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least another one of thesecond dummy apertures may be formed perpendicular to the mainapertures.

[0061] In another alternative process of forming the second electrodes,the second electrodes may be formed using an evaporation mask. Theevaporation mask may be drawn taut by application of tension and mayhave at least two mask units, through each of which the secondelectrodes of the organic EL devices may be deposited. The evaporationmask may comprise a plurality of second dummy apertures outside andadjacent to outermost mask units in the direction in which tension isapplied to the evaporation mask.

[0062] At least one of the second dummy apertures of the evaporationmask may be located outside the effective luminescent areas of theorganic EL device that may be deposited by the outermost mask unitsadjacent to the second dummy apertures.

[0063] The second dummy apertures may be formed parallel to the mainapertures of the mask units, and at least one of the second dummyapertures may be formed perpendicular to the main apertures.

[0064] According to another aspect of the present invention, there isprovided still another method of manufacturing an organic EL device. Inthis method, first electrodes are formed on a substrate in apredetermined pattern. Next, an organic film comprising an effectiveluminescent area is formed to cover at least the first electrodes byevaporating an organic material containing an organic luminescentmaterial. Thereafter, an evaporation mask to form second electrodes isdisposed over the organic film. Here, the evaporation mask is drawn tautby application of tension and comprises a plurality of main aperturesand a plurality of dummy apertures formed adjacent to the outermost onesof the main apertures in a direction in which tension is applied to theevaporation mask. Second electrodes are formed through the mainapertures so that the effective luminescent area is formed at an areawhere the first and second electrodes overlap. At this time, a seconddummy pattern area is formed outside the effective luminescent areathrough the first dummy apertures. Finally, the resulting structure issealed.

[0065] At least one of the first dummy apertures may be formed parallelto the main apertures, and at least another one of the first dummyapertures may be formed perpendicular to the main apertures.

[0066] At least two organic EL devices may be manufactured in a singleprocess. The evaporation mask may comprise at least two mask units,through each of which the second electrodes of a single organic ELdevice can be deposited, and a plurality of second dummy aperturesoutside and adjacent to outermost ones of the mask units in thedirection in which tension is applied to the evaporation mask.

[0067] The second dummy apertures of the evaporation mask may be locatedoutside the effective luminescent areas of the organic EL devices thatmay be deposited by the outermost mask units adjacent to the seconddummy apertures.

[0068] At least one of the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least another one of thesecond dummy apertures may be formed perpendicular to the mainapertures.

[0069] According to another aspect of the present invention, there isprovided still yet another method of manufacturing an organic EL device.In this method, first electrodes for an organic EL device are formed ona substrate. Next, an organic film comprising an effective luminescentarea is formed to cover at least the first electrodes by evaporating anorganic material containing an organic luminescent material. Anevaporation mask to form second electrodes is disposed over the organicfilm. Here, the evaporation mask is drawn taut by application of tensionand comprises at least two mask units. Each of the mask units comprisesa plurality of main apertures and a plurality of second dummy aperturesformed outside and adjacent to the outermost ones of the mask units in adirection in which tension is applied to the evaporation mask. Secondelectrodes are formed through the main apertures of each of the maskunits so that the effective luminescent area is formed at an area wherethe first and second electrodes overlap. Finally, the resultingstructure is sealed.

[0070] The second dummy apertures of the evaporation mask may be locatedoutside the effective luminescent areas of the organic EL devices thatmay be deposited by the outermost mask units adjacent to the seconddummy apertures.

[0071] At least one of the second dummy apertures may be formed parallelto the main apertures of the mask units, and at least one of the seconddummy apertures may be formed perpendicular to the main apertures.

[0072] According to still another aspect of the present invention, thereis provided an organic EL device including a substrate, an effectiveluminescent area, a terminal unit, a sealing unit, and a dummy patternarea. The effective luminescent area is formed by sequentially stackingfirst electrodes, an organic film including an organic luminescentlayer, and second electrodes on the substrate. The organic film emitslight at the area where the first and second electrodes overlap. Theterminal unit is formed on the edge of the substrate outside theeffective luminescent area and has a first electrode terminal connectedto the first electrodes and a second electrode terminal connected to thesecond electrodes. The sealing unit is formed on the substrate so as toexpose the terminal unit and seal at least the effective luminescentarea. The dummy pattern area is formed outside of the effectiveluminescent area.

[0073] The dummy pattern area may be formed between the effectiveluminescent area and the terminal unit.

[0074] The dummy pattern area may be formed inside an area sealed by thesealing unit.

[0075] The dummy pattern area may be formed of the same material as theorganic luminescent layer.

[0076] The dummy pattern area may be formed of the same material as theorganic film.

[0077] The dummy pattern area may be formed of the same material as thesecond electrodes.

[0078] The dummy pattern area may be formed on the outside of theorganic luminescent area in an upper area of the organic film.

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] These and/or other aspects and advantages of the invention willbecome apparent and more readily appreciated from the followingdescription of the embodiments, taken in conjunction with theaccompanying drawings of which:

[0080]FIG. 1 is an exploded perspective view of a conventionalevaporation mask;

[0081]FIG. 2 is a cross-section of part of the evaporation mask of FIG.1;

[0082]FIG. 3 is a plan view of the evaporation mask of FIG. 1;

[0083]FIG. 4 is a perspective view of an evaporation mask according toan embodiment of the present invention;

[0084]FIG. 5 is a partial perspective view of a mask unit of theevaporation mask of FIG. 4;

[0085]FIGS. 6 and 7 are cross-sections taken along line II-II of FIG. 5;

[0086]FIG. 8 is a graph showing deviation in the widths of apertures ina mask according to the present invention;

[0087]FIG. 9 is a plan view of the evaporation mask of FIG. 4;

[0088]FIGS. 10A through 10C are schematic views showing deviation of thetotal pitch of the evaporation mask of FIG. 4 and a line deviation ofthe evaporation mask;

[0089]FIG. 11 is a plan view of part of a mask unit of an evaporationmask according to another embodiment of the present invention;

[0090]FIGS. 12 and 13 are plan views of evaporation masks according todifferent embodiments of the present invention;

[0091]FIG. 14 is a perspective view of an evaporation mask according toyet another embodiment of the present invention;

[0092]FIG. 15 is a plan view of the evaporation mask of FIG. 14;

[0093]FIGS. 16 through 19 are plan views of evaporation masks accordingto different embodiments of the present invention;

[0094]FIGS. 20 through 29 are views for illustrating a method ofmanufacturing an organic electroluminescent (EL) device, according tothe present invention; and

[0095]FIG. 30 is an exploded perspective view of an organic EL deviceaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0096] Reference will now be made in detail to the embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below to explain the presentinvention by referring to the figures.

[0097] Referring to FIGS. 4 through 6, an evaporation mask 20 accordingto an embodiment of the present invention includes a plurality of maskunits 21. As shown in FIG. 4, the plurality of mask units 21 can bepatterned on many products in a single process. The evaporation mask 20may be a magnetic thin plate made of nickel or an alloy of nickel andcobalt. Preferably, the evaporation mask 20 is made of a nickel-cobaltalloy, which facilitates the formation of fine patterns and provides anexcellent surface roughness. Apertures 211 and 213 in the evaporationmask 20 may be formed in a predetermined pattern by an electro-formingmethod so as to obtain a fine pattern and an excellent surfacesmoothness. The alloy of Ni and Co may be composed of 85% by weightnickel and 15% by weight cobalt.

[0098] The evaporation mask 20 may be manufactured by an etching method,that is, by forming a photoresist layer having a pattern of apertures211 and 213 on a thin plate, or attaching a film having the pattern ofapertures 211 and 213 to a thin plate and then etching the resultingplate.

[0099] As shown in FIG. 4, tension is applied to the evaporation mask 20manufactured by the etching method in x- and y-axis directions while itsedges are fixed by a clamp or an adhesive agent. Then, the tautevaporation mask 20 is joined to a mask frame 30. The mask frame 30 ishollow so as to support the edge of the evaporation mask 20 excludingthe portion where the mask units 21 have been formed. The joining can beachieved by various methods, such as using an adhesive agent, a laserwelding method, or a resistance heating welding method. Especially, thelaser welding method can be used to overcome a problem such as anaccuracy change or the like. In FIG. 4, reference numeral 31 denotes awelding dot used in laser welding.

[0100] Although not shown in the drawings, a portion of the evaporationmask 20 to be welded to the mask frame 30 may be covered by a coverframe to prevent the evaporation mask 20 from coming off the mask frame30, in order to overcome stretching or warping of the evaporation maskdue to poor welding of the evaporation mask 20 to the mask frame 30.

[0101] As shown in FIG. 5, each of the mask units 21 included in theevaporation mask 20 includes a pattern of a plurality of apertures 211and 213, which are defined by strip-like shielding portions 212. Theapertures 211 and 213 shown in FIGS. 4 and 5 are elongated in parallelstraight lines. However, the apertures 211 and 213 are not limited tosuch strip shapes, and can be formed in various shapes and patterns,such as lattice or mosaic shapes. A rib 22 is installed between adjacentmask units 21 so as to keep a distance therebetween. The rib 22 can be afirst rib 221 for isolating mask units 21 arranged in the x-axisdirection, or a second rib 222 for isolating mask units 21 arranged inthe y-axis direction.

[0102] The apertures 213 are first dummy apertures located at theoutermost place in a direction in which tension is applied to theevaporation mask 20, while the apertures 211 are main apertures locatedinside the first dummy apertures 213. The first dummy apertures 213 areused to prevent apertures around the edge of each of the mask units frombeing deformed by tension applied to the evaporation mask 20. As shownin FIG. 5, because the main apertures 211 are formed in strips elongatedin the y-axis direction, apertures around the edge of each of the maskunits 21 may be deformed by the tension applied in the x-axis directionrather than by the tension applied in the y-axis direction. Accordingly,the first dummy apertures 213 are installed adjacent to some of the mainapertures 211 located at the outer side in the x-axis direction. Here,the main apertures 211 are used to form an effective deposition areathat allows a deposition to form a pattern desired by a user, while thefirst dummy apertures 213 are used to form an ineffective depositionarea.

[0103]FIG. 6 is a cross-section taken along line II-II of FIG. 5. Firstthrough third shielding portions 212 a through 212 c are sequentiallyformed in the x-axis direction starting from a first rib 221 to form amask unit 21. First and second main apertures 211 a and 211 b aresequentially formed in the x-axis direction between the first and secondshielding portions 212 a and 212 b and between the second and thirdshielding portions 212 b and 212 c, respectively. A first dummy aperture213 is formed between the first rib 221 and the first shielding portion212 a.

[0104] In FIG. 6, the width Wsl of the first main aperture 211 a has adeviation of ΔWs1, and the width Ws2 of the second main aperture 211 bhas a deviation of ΔWs2. ΔWr1 denotes a deviation of the width Wr1 ofthe first shielding portion 212 a, and ΔWsd denotes a deviation of thewidth Wsd of the first dummy aperture 213.

[0105] As shown in FIG. 7, when tension is applied to the evaporationmask having the apertures with the above widths, an edge 221 a of thefirst rib 221 that defines the first dummy aperture 213 located at theedge area of the mask unit 21 is lifted upward or downward due to theextension of the evaporation mask in the x-axis direction shown in FIGS.4 and 5. Hence, the deviation ΔWsd of the width Wsd of the first dummyaperture 213 increases. The deviation of the apertures of theevaporation mask after application of tension is shown in FIG. 8. InFIG. 8, reference character A refers to an evaporation mask manufacturedby electroforming, and reference character B refers to an evaporationmask manufactured by etching. Since the deviation of the width of eachof the main apertures typically depends on the deviations of the widthsof the shielding portions, ΔWr1, ΔWr2, ΔWr3, . . . , the deviations ofthe widths of the first dummy aperture 213 and the first and second mainapertures 211 a and 211 b, ΔWsd, ΔWs1, and ΔWs2, shown in FIG. 8, aredivided by the deviation ΔWr1 of the width of the first shieldingportion and then expressed as percentage.

[0106] As shown in FIG. 8, after tension is applied to the evaporationmask, the deviation ΔWsd of the width of the first dummy aperture 213increases by 25 to 75% of the deviation ΔWr1 of the width of the firstshielding portion due to deformation of the edge 221 a of the first rib221. The deviations of the widths of the first and second main apertures211 a and 211 b, ΔWs1 and ΔWs2, are nearly the same as the deviationΔWr1 of the width of the first shielding portion.

[0107] According to the experiment of FIG. 8, because the first dummyaperture 213 is deformed when tension is applied in the x-axisdirection, deformation of the main apertures 211 forming an effectivedeposition area is minimized, and accordingly, highly accuratepatterning can be achieved.

[0108] As shown in FIG. 9, because the first dummy apertures 213 existat the outermost edges of each of the mask units 21, the total pitch Ptis determined as the interval between lines C and D which connect theoutermost first main apertures 211 a of two mask units 21 a in thex-axis direction. As shown in FIGS. 10A and 10B, the total pitch Pt mayhave a deviation (Pt max−Pt min). As shown in FIGS. 10A through 10C, aline deviation (ΔX) may be generated. Hence, the evaporation mask 20 andthe mask frame 30 must be welded together while controlling tension forlocal areas so as to reduce both deviation of the total pitch and linedeviation.

[0109] As shown in FIG. 5, the first dummy apertures 213 may have thesame shape and width as the main apertures 211, and may be spaced apartfrom an adjacent first main aperture 211 a by the same interval as theinterval between adjacent main apertures 211. However, the first dummyapertures 213 are not limited to the above shape and pattern; any shapeand pattern may be adopted as long as the pattern of the main apertures211 is not affected. For example, as shown in FIG. 11, the width Wsd ofa first dummy aperture 213 may be smaller than the width Ws1 of a firstmain aperture 211 a, and the width Wr1 of the first shielding portion212 a between the first dummy aperture 213 and the first main aperture211 a may be greater than the width Wr2 of the second shielding portion212 b between the first and second main apertures 211 a and 211 b.Although not shown in the drawings, various shapes and patterns may beapplied.

[0110] The above-described way of shaping and installing first dummyapertures 213 is equally applied to the case of FIG. 12, where the mainapertures 211 of each of the mask units 21 are arranged in a latticepattern. However, the lattice shape of the main apertures 211 causesboth tension in the x- and y-axis directions to affect the accuracy ofpatterning. Hence, the first dummy apertures 213 are formed near themain apertures located at the outermost edges of each of the mask units21. As shown in FIG. 12, the first dummy apertures 213 may have a lengthcorresponding to the length of one side of a mask unit 21 and be formedat each side of each mask unit. Alternatively, although not shown in thedrawings, a plurality of first dummy apertures having a lengthcorresponding to the length of one side of each of the lattice-like mainapertures 211 may be arranged at each side of each mask unit.

[0111] The installation of the first dummy apertures 213 of FIG. 12 canalso be applied to an evaporation mask 20 of FIG. 13, which includesopen mask units 21 that each have a single main aperture 211.

[0112] As shown in FIG. 14, an evaporation mask 20 according to yetanother embodiment of the present invention includes second dummyapertures 22 to improve accuracy. FIG. 15 is a plan view of theevaporation mask 20 of FIG. 14.

[0113] As shown in FIGS. 14 and 15, the evaporation mask 20 includes atleast two mask units 21 having a predetermined pattern of main apertures211. At least one second dummy aperture 22 is formed outside the maskunits 21 such as to be adjacent to mask units 21 a and 21 b located atthe outermost edges in the direction where tension is applied.

[0114] As shown in FIG. 14, if the main apertures 211 of the evaporationmask 20 are strips elongated in the y-axis direction, they are seriouslydeformed in the x-axis direction, and accordingly, the total pitch Pt isdistorted in the x-axis direction. The distortion of the total pitch Ptis prevented by forming the second dummy apertures 22 so as to beadjacent to columns of masks 21 a and masks 21 b that are located on theedges of the evaporation mask 20, particularly, at the outermost sidesin the x-axis direction. Here, because the second dummy apertures 22 aredeformed due to tension applied in the x-axis direction, the mainapertures 211 formed inside the second dummy apertures 22 are preventedfrom being deformed due to the tension. Consequently, the total pitch Ptis compensated.

[0115] As shown in FIGS. 14 and 15, the second dummy apertures 22 can beformed in the same shape and with the same width as the main apertures211. However, the second dummy apertures 22 can have various shapes andpatterns as long as they don't affect the pattern of the main apertures211. Also, the second dummy apertures 22 may be formed on the exteriorsides of the outermost mask units 21 a and 21 b so as to be as close aspossible to the outermost mask units 21 a and 21 b without interferingwith deposition areas desired by a user, that is, with effectivedeposition areas where deposition is achieved through the outermost maskunits 21 a and 21 b. Of course, the second dummy apertures 22 must belocated inside the welding dots 31 of the evaporation mask 20.

[0116] On the other hand, as shown in FIG. 16, if alignment marks 23 areformed outside a configuration of mask units 21 in order to assist inalignment with a substrate where deposition is to be performed, thealignment marks 23 must not be deformed when tension is applied to theevaporation mask 20. If the alignment marks 23 are deformed, theevaporation mask 20 is not properly aligned with the substrate, thuscausing distortion of the total pitch and inaccurate patterning.

[0117] To avoid deformation of the alignment marks 23, a pair of seconddummy apertures 221 and 222 is formed at both sides of each of thealignment marks 23. The inner second dummy aperture 221 prevents thetotal pitch Pt from being distorted, thereby increasing the accuracy ofpatterning. The outer second dummy aperture 222 prevents the alignmentmarks 23 from being deformed, thereby accurately aligning the substratewith the evaporation mask 20.

[0118] As shown in FIG. 17, the second dummy apertures 22 can be equallyapplied to the case where the main apertures 211 of each of the maskunits 21 are formed in a lattice pattern. However, because the mainapertures 211 have a lattice pattern, a tension in the y-axis directionas well as a tension in the x-axis direction adversely affects theaccuracy of the total pitch Pt, so second dummy apertures 22 are alsoformed adjacent to the main apertures located at the outermost sides inthe y-axis direction. The way of installing the second dummy apertures22 as in FIG. 17 is also applied to an evaporation mask 20 of FIG. 18including open mask units 21, each formed of a single main aperture 211.

[0119] Since the evaporation mask 20 having the second dummy apertures22 described with reference to FIGS. 14 through 18 does not include thefirst dummy apertures 213, the total pitch corresponds to the intervalbetween the outermost main apertures in the outermost mask units.However, the evaporation mask 20 according to the present invention isnot limited to the above determination of the length of the total pitch,but can be formed of a combination of the first dummy apertures 213 andthe second dummy apertures 22 as shown in FIG. 19. Here, the combinationof the first and second dummy apertures 213 and 22, respectively, may bea combination of all of the above-described embodiments.

[0120] In the evaporation mask 20 of FIG. 19, having the first andsecond dummy apertures 213 and 22, respectively, each of the mask units21 prevents deformation of its main apertures forming an effectivedeposition area and improves the accuracy of the total pitch. Thus,highly accurate patterning can be achieved.

[0121] A method of manufacturing an organic EL device using theabove-described evaporation mask 20 according to the present inventionwill now be described with reference to FIGS. 20 through 30. Referringto FIG. 20, first, a transparent conductive film 43 and a metalconductive film 44 are sequentially stacked on a transparent substrate41. The transparent conductive film 43 may be formed of ITO, and themetal conductive film 44 may be formed of chrome (Cr). The substrate 41may be formed of transparent glass, plastic, or the like. Before thetransparent conductive film 43 and the metal conductive film 44 areformed on the substrate 41, a buffer layer 42 may be formed to provide asmooth substrate and prevent penetration of impure atoms. The bufferlayer 42 may be formed of SiO₂. The substrate 41 may be large enough toform at least two organic EL devices thereon through a single process.

[0122] Next, as shown in FIG. 21, external electrode terminals 441 and442, which may serve as first and second electrode terminals,respectively, are formed by processing the metal conductive film 44formed on the upper surface of the substrate 41. FIG. 21 refers to thecase where a plurality of organic EL devices are manufactured in asingle process. However, for convenience of explanation, the manufactureof a single organic EL device will now be described by cutting off anorganic EL device from the plurality of EL devices as shown in FIG. 21.

[0123]FIG. 22A refers to an organic EL device of FIG. 21, and FIG. 22Bis a cross-section taken along line III-III of FIG. 22A. As shown inFIGS. 22A and 22B, the external electrode terminals 441 and 442 are thebasis of the formation of the first and second electrode terminals 51and 52 of FIG. 23A, and the transparent conductive film 43 is partiallyexposed on the substrate 41.

[0124] Thereafter, as shown in FIGS. 23A through 23C, internal electrodeterminals 431 and 432 for the first and second electrodes 51 and 52 anda predetermined pattern of transparent conductive lines 433 are formedby patterning the exposed portion of the transparent conductive film 43on the substrate 41. The transparent conductive lines 433 are connectedto the first electrode terminals 51 and serve as first electrode lines61. FIG. 23B is a cross-section taken along line IV-IV of FIG. 23A, andFIG. 23C is a cross-section taken along line V-V of FIG. 23A. Thepatterning of the transparent conductive film 43 may be achieved byphotolithography.

[0125] Next, as shown in FIGS. 24A and 24B, an inter-insulator 64 isformed between adjacent first electrode lines 61. FIG. 24B is across-section taken along line VI-VI of FIG. 24A. The inter-insulator 64may be formed of photoresist, photosensitive polyimide, or the likeusing a photolithography method or the like.

[0126] Although not shown in the drawings, at the same time theinter-insulator 64 is formed, a shielding wall may be further formedinside and outside a place to be coated with an adhesive agent so as toseal up a cap, and an outer-insulator may be formed between the firstelectrode line 61 and the second electrode terminal 52. As describedlater, the outer-insulator is formed to prevent problems such asdisconnection due to the step difference between second electrode linesand the second electrode terminals 52 upon formation of the secondelectrode lines. A buffer layer may be further formed below theouter-insulator by processing the transparent conductive film 43 toimprove the adhesive strength between the outer-insulator and asubstrate. Separators may be simultaneously formed to form an organic ELfilm and a pattern of second electrode lines. Partitions for preventingthe organic EL film from being damaged may be formed simultaneously.Shielding portions may be formed simultaneously on the place to becoated with an adhesive agent.

[0127] Then, an organic film is deposited using an evaporation apparatusshown in FIG. 25. In the evaporation apparatus of FIG. 25, anevaporation source 92 for evaporating an organic material is installedwithin a chamber 91 in a vacuum state, and the evaporation mask 20supported by the mask frame 30 is installed over the evaporation source92. As described above, the substrate 41 having first electrode linesand an inter-insulator formed thereon is mounted over the evaporationmask 20. A magnet unit 93 is closely installed over the substrate 41.

[0128] As shown in FIGS. 26A through 26C, an organic film 63 isdeposited using an evaporation apparatus as shown in FIG. 25. Theorganic film 63 can be any organic film used in an organic EL device,and can be formed by stacking a hole transport layer, an organicluminescent layer, an electron transport layer, and the like to form asingle or complex structure. The organic film 63 can be made of variousorganic materials including copper phthalocyanine (CuPc), N, N′-Di(naphthalene-1-yl)-N, N′-diphenyl-benzidine (NPB), andtris-8-hydroxyquinoline aluminum (Alq3). In the case of full colororganic EL devices, the organic film 63 can be formed in variouspatterns such that the patterned organic luminescent layer correspondsto the color of each pixel.

[0129] The organic film 63 may be formed after the evaporation mask 20is mounted on the evaporation apparatus of FIG. 25. Here, theevaporation mask 20 may be the evaporation mask 20 according to any ofthe embodiments of the present invention described with reference toFIGS. 4 through 19.

[0130] In other words, as described above with reference to FIGS. 4through 13, the evaporation mask 20 having the main apertures 211 andthe first dummy apertures 213 can be used to form an organic film. Here,the first dummy apertures 213 are formed adjacent to the outermost mainapertures 211 a in a direction in which tension is applied, i.e., in adirection perpendicular to the direction of the length of the mainapertures 211. Also, as described above with reference to FIGS. 14through 19, the evaporation mask 20 having the second dummy apertures22, included in at least two mask units for forming an organic ELdevice, can be used to form an organic film. Here, the second dummyapertures 22 are formed outside the mask units, adjacent to mask unitsin a direction in which tension is applied, i.e., in a directionperpendicular to the direction of the length of the main apertures 211.Furthermore, although not shown in the drawings, an evaporation maskhaving both the first and second dummy apertures 213 and 22,respectively, can be used to form an organic film.

[0131] As shown in FIG. 26C, a first dummy pattern area 70 is formed bythe first dummy apertures 213. FIG. 26C is a partially magnifiedcross-section of the portion indicated by reference character VIII.

[0132] As shown in FIGS. 26A through 26C, the organic film 63 is formedby depositing a hole transport layer 631 on the first electrode lines 61and the inter-insulators 64 and then depositing red (R), green (G), andblue (B) organic luminescent layers 632 on the hole transport layer 631such as to form color patterns. Here, the hole transport layer 631 canbe blanket deposited without patterns, and the organic luminescentlayers 632 may be formed in a pattern. In FIG. 26C, the organicluminescent layers 632 having a pattern are deposited using theabove-described evaporation masks according to the present invention. Asdescribed above, the R, G, and B organic luminescent layers 632, formedon the first electrode lines 61, correspond to areas where the firstelectrode lines intersect with the second electrode lines, andaccordingly emit light in response to the application of power. Thus,the R, G, and B organic luminescent layers 632 form an effectiveluminescent area 60.

[0133] As shown in FIG. 26C, if the R, G, and B organic luminescentlayers 632 are deposited using the evaporation mask having the firstdummy apertures, dummy organic luminescent layers 632 a are furtherdeposited between the second electrode terminals 52 and the firstelectrode lines 61, that is, the effective luminescent area 60, throughthe first dummy apertures. The dummy organic luminescent layers 632 aform the first dummy pattern area 70.

[0134] As shown in FIG. 27, if the hole transport layer 631 is depositedusing an evaporation mask for forming an organic film as shown in FIG.13, the first dummy pattern area 70 further includes a dummy holetransport layer 631 a. Here, although not shown in the drawings, organicfilms can be deposited to the same height in the first dummy patternarea 70 by controlling the widths of the first dummy apertures 213 ofFIG. 13.

[0135] As described above, if evaporation masks capable of forming thefirst dummy pattern area 70 have second dummy apertures, the variationof the total pitch is reduced to thus improve the accuracy of patterningof the effective luminescent area, particularly the organic luminescentlayers.

[0136] Since the first dummy pattern area 70 is formed outside theeffective luminescent area 60 where the first electrode lines intersectwith the second electrode lines, that is, formed in an area where thefirst electrode lines do not intersect with the second electrode lines,the first dummy pattern area 70 corresponds to an ineffectiveluminescent area where no light emission occurs. The deposition using anevaporation mask capable of forming the first dummy pattern area 70contributes to improvement of the accuracy of patterning in theeffective luminescent area 60.

[0137] As shown in FIGS. 28A and 28B, after the organic film 63 isdeposited, the second electrode lines 62 may be formed of aluminum (Al)or calcium (Ca) in a predetermined pattern on the organic film 63 suchas to intersect with the first electrode lines 61. Like the depositionof the organic film 63, the second electrode lines 62 may be formedusing an evaporation mask in an evaporation apparatus as shown in FIG.25. At this time, the second electrode lines 62 may be patterned usingan evaporation mask having a predetermined pattern or by previouslyinstalling a separator for forming a pattern and then performing blanketdeposition on the separator.

[0138] For example, as in the deposition of the organic film 63 havingthe organic luminescent layers 632, the second electrode lines 62 can bepatterned using the evaporation mask having first and/or second dummyapertures described with reference to FIGS. 4 through 19. FIG. 29 showsan example of patterning the second electrode lines 62 using anevaporation mask. To be more specific, when the evaporation mask 20 ofFIG. 4, having a pattern of main apertures 211 and the first dummyapertures 213, is used to form the second electrode lines 62, seconddummy electrode lines 62 a are deposited on the exterior side of theeffective luminescent area 60, which is where the organic film 63 emitslight due to the crossing of the first and second electrode lines 61 and62. The second dummy electrode lines 62 a form a second dummy patternarea 71. Because the second dummy electrode lines 62 a are not connectedto second electrode terminals which receive external power, the seconddummy pattern area 71 corresponds to an ineffective luminescent areawhere no light emission occurs, as in the first dummy pattern area 70.As shown in FIG. 29, preferably, the second dummy electrode lines 62 amay be formed outside the effective luminescent area 60 on the uppersurface of the organic film 63 so as not to contact the first electrodelines 61.

[0139] A method of depositing an organic film using an evaporation maskforming an organic film and depositing second electrode lines using anevaporation mask forming second electrodes is described above. However,it is natural that the second electrode lines may be deposited using anevaporation mask according to the present invention regardless of whichevaporation mask is used to deposit the organic film.

[0140] As shown in FIG. 30, if an organic film and second electrodelines are completely formed, a sealing cap 81 is joined to the substrate41 so as to serve as a sealing portion 80. A flexible printed circuitboard 82 is connected to the first and second electrode terminals 51 and52 exposed to the outside of the sealing portion 80, thereby completingthe assembly of an organic EL device. The sealing may be achieved by anyother methods applied to organic EL devices.

[0141] As shown in FIG. 30, the organic EL device according to thepresent invention has the effective luminescent area 60 where an organicfilm is formed between the first and second electrode lines 61 and 62.The organic EL device according to the present invention also includes aterminal unit 50 having the first and second electrode terminals 51 and52, which supply power to the first and second electrode lines 61 and62, respectively, of the effective luminescent area 60. Furthermore, theorganic EL device according to the present invention may include thesecond dummy pattern area 71 and/or the first dummy pattern area 70,which is formed outside the effective luminescent area 60, that is,between the effective luminescent area 60 and the terminal unit 50.Since the structures and functions of the components of the organic ELdevice according to the present invention have been described withreference to FIGS. 20 through 29, they will not be described here indetail.

[0142] As described above, according to the present invention, anorganic EL device having first and/or second dummy pattern areas in anineffective luminescent area is manufactured using an evaporation maskhaving first and/or second dummy apertures, thereby improving theaccuracy of patterning of an effective luminescent area where lightemission occurs.

[0143] The present invention has the following effects. Firstly, theaccuracy of the patterning of an effective deposition area may beimproved.

[0144] Secondly, if several devices are formed at one time in a singleprocess, the accuracy of the total pitch is improved, and thus themanufacturing yield may be improved.

[0145] Thirdly, a substrate may be accurately aligned with anevaporation mask.

[0146] Fourthly, because an organic EL device according to the presentinvention includes a dummy pattern area, that is, an ineffectiveluminescent area, an effective luminescent area where light emissionoccurs may have smaller pixels, resulting in a finer resolution.

[0147] Fifthly, even when tension is applied to an evaporation mask totautly support the evaporation mask, the accuracy of the pattern of theevaporation mask is not degraded.

[0148] Although a few embodiments of the present invention have beenshown and described, it would be appreciated by those skilled in the artthat changes may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

What is claimed is:
 1. An evaporation mask formed of a thin film,wherein the evaporation mask is drawn taut by application of tension andcomprises: at least one mask unit, comprising: a plurality of mainapertures, and a plurality of first dummy apertures formed adjacent tooutermost ones of the main apertures in a direction in which tension isapplied to the evaporation mask.
 2. The evaporation mask of claim 1,wherein the main apertures form an effective deposition area, and thefirst dummy apertures form an ineffective deposition area.
 3. Theevaporation mask of claim 2, wherein at least one of the first dummyapertures is formed parallel to the main apertures, and at least anotherone of the first dummy apertures is formed perpendicular to the mainapertures.
 4. The evaporation mask of claim 2, comprising at least twomask units, and further comprising a plurality of second dummy aperturesformed outside and adjacent to the outermost mask units in the directionin which tension is applied to the evaporation mask.
 5. The evaporationmask of claim 4, wherein the second dummy apertures are formed outsidethe effective deposition areas where the mask units are formed.
 6. Theevaporation mask of claim 4, wherein at least one of the second dummyapertures is formed parallel to the main apertures of the mask units,and at least another one of the second dummy apertures is formedperpendicular to the main apertures.
 7. An evaporation mask formed of athin film, wherein the evaporation mask is drawn taut by application oftension, the evaporation mask comprising: at least two mask units eachhaving at least one main aperture; and at least one second dummyaperture formed outside and adjacent to the mask units located at theoutermost sides in the direction in which tension is applied to theevaporation mask.
 8. The evaporation mask of claim 7, wherein the atleast one main aperture of each of the mask units is used to form aneffective deposition area, and the at least one second dummy aperture isformed outside of the effective deposition areas where the mask unitsare formed.
 9. The evaporation mask of claim 7, wherein the at least onesecond dummy aperture comprises at least two second dummy apertures,wherein at least one of the second dummy apertures is formed parallel tothe at least one main aperture of the mask units, and at least anotherone of the second dummy apertures is formed perpendicular to the atleast one main aperture.
 10. A method of manufacturing an organicelectroluminescent (EL) device, the method comprising: forming firstelectrodes on a substrate; disposing an evaporation mask to form anorganic film over the substrate, the evaporation mask drawn taut byapplication of tension and having at least one mask unit, the mask unitcomprising a plurality of main apertures and a plurality of first dummyapertures formed adjacent to outermost ones of the main apertures in adirection in which tension is applied to the evaporation mask; formingthe organic film comprising an effective luminescent area to cover atleast the first electrodes by evaporating an organic material containingan organic luminescent material through the main apertures, and forminga first dummy pattern area outside the effective luminescent areathrough the first dummy apertures; forming second electrodes on theorganic film so that the effective luminescent area is formed at an areawhere the first and second electrodes overlap; and sealing the resultingstructure.
 11. The method of claim 10, wherein at least one of the firstdummy apertures is formed parallel to the main apertures, and at leastanother one of the first dummy apertures is formed perpendicular to themain apertures.
 12. The method of claim 10, wherein at least two organicEL devices are manufactured in a single process, and the evaporationmask comprises at least two mask units, through each of which theorganic film of a single organic EL device can be deposited, and aplurality of second dummy apertures outside and adjacent to outermostones of the mask units in the direction in which tension is applied tothe evaporation mask.
 13. The method of claim 12, wherein the seconddummy apertures of the evaporation mask are located outside theeffective luminescent areas of the organic EL devices that are depositedby the outermost mask units adjacent to the second dummy apertures. 14.The method of claim 12, wherein at least one of the second dummyapertures is formed parallel to the main apertures of the mask units,and at least another one of the second dummy apertures is formedperpendicular to the main apertures.
 15. The method of claim 10, whereinin forming the second electrodes, an evaporation mask to form the secondelectrodes is disposed over the substrate, the evaporation mask drawntaut by application of tension and having at least one mask unit, themask unit comprising a plurality of main apertures and a plurality offirst dummy apertures formed adjacent to the outermost main apertures inthe direction in which tension is applied to the evaporation mask, thesecond electrodes are formed on the effective luminescent area throughthe main apertures, and a second dummy pattern area is formed outsidethe effective luminescent area through the first dummy apertures. 16.The method of claim 15, wherein at least one of the first dummyapertures is formed parallel to the main apertures, and at least anotherone of the first dummy apertures is formed perpendicular to the mainapertures.
 17. The method of claim 15, wherein at least two organic ELdevices are manufactured in a single process, and the evaporation maskcomprises at least two mask units, through each of which the secondelectrodes of a single organic EL device can be deposited, and aplurality of second dummy apertures outside and adjacent to theoutermost mask units in the direction in which tension is applied to theevaporation mask.
 18. The method of claim 17, wherein the second dummyapertures are located outside the effective luminescent areas of theorganic EL devices that are deposited by the outermost mask unitsadjacent to the second dummy apertures.
 19. The method of claim 17,wherein at least one of the second dummy apertures is formed parallel tothe main apertures of the mask units, and at least another one of thesecond dummy apertures is formed perpendicular to the main apertures.20. The method of claim 10, wherein at least two organic EL devices aremanufactured in a single process, the second electrodes are formed usingan evaporation mask drawn taut by application of tension and having atleast two mask units, through which the second electrodes of the organicEL devices can be deposited, and the evaporation mask comprises aplurality of second dummy apertures outside and adjacent to outermostmask units in the direction in which tension is applied to theevaporation mask.
 21. The method of claim 20, wherein the second dummyapertures are located outside the effective luminescent areas of theorganic EL devices that are deposited by the outermost mask unitsadjacent to the second dummy apertures.
 22. The method of claim 20,wherein at least one of the second dummy apertures is formed parallel tothe main apertures of the mask units, and at least another one of thesecond dummy apertures is formed perpendicular to the main apertures.23. A method of manufacturing an organic EL device, the methodcomprising: forming first electrodes for an organic EL device on asubstrate; disposing an evaporation mask to form an organic film overthe substrate, the evaporation mask drawn taut by application of tensionand including at least two mask units each comprising a plurality ofmain apertures and a plurality of second dummy apertures formed outsideand adjacent to outermost ones of the mask units in a direction in whichtension is applied to the evaporation mask; forming the organic filmcomprising an effective luminescent area to cover at least the firstelectrodes by evaporating an organic material containing an organicluminescent material through the main apertures of each of the maskunits; forming second electrodes on the organic film so that theeffective luminescent area is formed at an area where the first andsecond electrodes overlap; and sealing the resulting structure.
 24. Themethod of claim 23, wherein the second dummy apertures are locatedoutside the effective luminescent areas of the organic EL devices thatare deposited by outermost ones of the mask units adjacent to the seconddummy apertures.
 25. The method of claim 23, wherein at least one of thesecond dummy apertures is formed parallel to the main apertures of themask units, and at least another one of the second dummy apertures isformed perpendicular to the main apertures.
 26. The method of claim 23,wherein in forming the second electrodes, an evaporation mask to formthe second electrodes is disposed over the substrate, the evaporationmask drawn taut by application of tension and including at least twomask units, the mask units each comprising a plurality of main aperturesand a plurality of first dummy apertures formed adjacent to theoutermost main apertures in the direction in which tension is applied tothe evaporation mask, the second electrodes are formed on each of theeffective luminescent areas through the main apertures, and a seconddummy pattern area is formed outside each of the effective luminescentareas through the first dummy apertures.
 27. The method of claim 26,wherein at least one of the first dummy apertures is formed parallel tothe main apertures, and at least another one of the first dummyapertures is formed perpendicular to the main apertures.
 28. The methodof claim 26, wherein the evaporation mask comprises a plurality ofsecond dummy apertures outside and adjacent to the outermost mask unitsin the direction in which tension is applied to the evaporation mask.29. The method of claim 28, wherein the second dummy apertures of theevaporation mask are located outside the effective luminescent areas ofthe organic EL devices that are deposited by the outermost mask unitsadjacent to the second dummy apertures.
 30. The method of claim 28,wherein at least one of the second dummy apertures is formed parallel tothe main apertures of the mask units, and at least another one of thesecond dummy apertures is formed perpendicular to the main apertures.31. The method of claim 23, wherein the second electrodes are formedusing an evaporation mask drawn taut by application of tension andhaving at least two mask units, through each of which the secondelectrodes of the organic EL devices are deposited, and the evaporationmask comprises a plurality of second dummy apertures outside andadjacent to outermost mask units in the direction in which tension isapplied to the evaporation mask.
 32. The method of claim 31, wherein thesecond dummy apertures of the evaporation mask are located outside theeffective luminescent areas of the organic EL devices that are depositedby the outermost mask units adjacent to the second dummy apertures. 33.The method of claim 31, wherein at least one of the second dummyapertures is formed parallel to the main apertures of the mask units,and at least one of the second dummy apertures is formed perpendicularto the main apertures.
 34. A method of manufacturing an organic ELdevice, the method comprising: forming first electrodes on a substratein a predetermined pattern; forming an organic film comprising aneffective luminescent area to cover at least the first electrodes byevaporating an organic material containing an organic luminescentmaterial; disposing an evaporation mask to form second electrodes overthe organic film, the evaporation mask drawn taut by application oftension and comprising a plurality of main apertures and a plurality ofdummy apertures formed adjacent to outermost ones of the main aperturesin a direction in which tension is applied to the evaporation mask;forming the second electrodes through the main apertures so that theeffective luminescent area is formed at an area where the first andsecond electrodes overlap, and forming a second dummy pattern areaoutside the effective luminescent area through the first dummyapertures; and sealing the resulting structure.
 35. The method of claim34, wherein at least one of the first dummy apertures is formed parallelto the main apertures, and at least another one of the first dummyapertures is formed perpendicular to the main apertures.
 36. The methodof claim 34, wherein at least two organic EL devices are manufactured ina single process, and the evaporation mask comprises at least two maskunits, through each of which the second electrodes of a single organicEL device can be deposited, and a plurality of second dummy aperturesoutside and adjacent to outermost ones of the mask units in thedirection in which tension is applied to the evaporation mask.
 37. Themethod of claim 36, wherein the second dummy apertures of theevaporation mask are located outside the effective luminescent areas ofthe organic EL devices that are deposited by the outermost mask unitsadjacent to the second dummy apertures.
 38. The method of claim 36,wherein at least one of the second dummy apertures is formed parallel tothe main apertures of the mask units, and at least another one of thesecond dummy apertures is formed perpendicular to the main apertures.39. A method of manufacturing an organic EL device, the methodcomprising: forming first electrodes for an organic EL device on asubstrate; forming an organic film comprising an effective luminescentarea to cover at least the first electrodes by evaporating an organicmaterial containing an organic luminescent material; disposing anevaporation mask to form second electrodes over the organic film, theevaporation mask drawn taut by application of tension and comprising atleast two mask units comprising a plurality of main apertures and aplurality of second dummy apertures formed outside and adjacent tooutermost ones of the mask units in a direction in which tension isapplied to the evaporation mask; forming the second electrodes throughthe main apertures of each of the mask units so that the effectiveluminescent area is formed at an area where the first and secondelectrodes overlap; and sealing the resulting structure.
 40. The methodof claim 39, wherein the second dummy apertures of the evaporation maskare located outside the effective luminescent areas of the organic ELdevices that are deposited by the outermost mask units adjacent to thesecond dummy apertures.
 41. The method of claim 39, wherein at least oneof the second dummy apertures is formed parallel to the main aperturesof the mask units, and at least one of the second dummy apertures isformed perpendicular to the main apertures.
 42. An organic EL devicecomprising: a substrate; an effective luminescent area formed bysequentially stacking first electrodes, an organic film including anorganic luminescent layer, and second electrodes on the substrate,wherein the organic film emits light at the area where the first andsecond electrodes overlap; a terminal unit formed on the edge of thesubstrate outside the effective luminescent area, the terminal unithaving a first electrode terminal connected to the first electrodes anda second electrode terminal connected to the second electrodes; asealing unit formed on the substrate so as to expose the terminal unitand seal at least the effective luminescent area; and a dummy patternarea formed outside of the effective luminescent area.
 43. The organicEL device of claim 42, wherein the dummy pattern area is formed betweenthe effective luminescent area and the terminal unit.
 44. The organic ELdevice of claim 42, wherein the dummy pattern area is formed inside anarea sealed by the sealing unit.
 45. The organic EL device of claim 42,wherein the dummy pattern area is formed of the same material as theorganic luminescent layer.
 46. The organic EL device of claim 42,wherein the dummy pattern area is formed of the same material as theorganic film.
 47. The organic EL device of claim 42, wherein the dummypattern area is formed of the same material as the second electrodes.48. The organic EL device of claim 42, wherein the dummy pattern area isformed outside of the organic luminescent area in an upper area of theorganic film.
 49. An evaporation mask formed of a thin film, wherein theevaporation mask is drawn taut by application of tension, theevaporation mask comprising: at least one mask unit comprising: at leastone main aperture, and at least one first dummy aperture formed adjacentto an outermost at least one main aperture in a direction in whichtension is applied to the evaporation mask.
 50. The evaporation mask ofclaim 49, further comprising at least one second dummy aperture formedoutside and adjacent to the outermost at least one mask unit in thedirection in which tension is applied to the evaporation mask.
 51. Amask unit for an evaporation mask, comprising: a main aperture; and adummy aperture; wherein the dummy aperture prevents the main aperturefrom being deformed by tension applied to the evaporation mask.